Learn about performance optimization.
Performance of web applications heavily depends on their size and how often a browser has to request static content like images, CSS and JavaScript files. To improve performance, most web servers support on-the-fly HTTP response compression and provide settings that enable you to configure how long browsers may cache a file before requesting it again. The HTTP response compression is usually implemented using gzip encoding (for example, mod_deflate in Oracle HTTP Server), while browser file caching is enabled by issuing Cache-Control HTTP response header (for example, using mod_headers in Oracle HTTP Server).
See your web server documentation to learn how to enable response compression and browser file caching. For optimal performance of the Oracle Application Express development environment and Oracle Application Express applications, Oracle recommends enabling gzip compression of files in the virtual images directory (for example, /i/) and responses from the database access descriptor (for example, /pls/apex), as well as allowing browsers to cache files from the virtual images directory for at least 12 hours.